This invention relates to a method enabling a device, for example a smartphone, to determine its own position.
With the developing of telecommunications, many solutions for tracking a mobile device have been proposed. The location information reported by such solutions are used in providing position-based services such as emergency rescue, locating a shop, searching for missing people, etc.
The GPS (Global Positioning System) technology uses information sent from GPS satellites. Such a technology requires a GPS receiver to be embedded in a mobile device to be tracked. One of the drawbacks of this technology is its cost relatively to precision of the location information reported. Indeed, the more precise the location information the more expansive the GPS receiver.
Another method for tracking the location of a mobile device is the triangulation technology. A mobile device receives signals from at least three base stations, and determines its relative location with respect to each of these three base stations using each base station coordinates and signal emitting time.
Such a method requires precise time synchronization between the base stations and the mobile device.
In order to overcome these deficiencies, methods for tracking the position of a mobile device using only one base station have been proposed.
U.S. Pat. No. 6,300,905 discloses a method for tracking the location of a mobile device using CDMA (Code Division Multiple Access) and TDMA (Time Division Multiple Access) systems. In the method disclosed, the base station measures the mobile device radio frequency forward link signal and the propagation-delay time to calculate the distance between the mobile device and the base station, and utilizes at least three multiple sector antennas to measure the mobile device's azimuth angle.
However, such a method does not provide precise location information of the mobile device because the resolution and precision of the measurement depend on the number of antennas used.